This invention relates to a coordinate measuring method and apparatus, and in particular, it relates to such a device using optical sensing means.
Existing coordinate measuring machines utilize a mechanical probe known as the Renishaw probe. However, the known probes are expensive, slow (because they must contact the surface or part being sensed), prone to breakage (again, because they must contact the part being sensed) and inaccurate in certain applications.
In general, the problem with respect to a coordinate measuring machine is to move the mechanical arm, the encoded coordinates of which are used to perform the measurement, and to move the probe into a position such that it can register against some feature of the part being sensed such as a bore wall, a flange face, etc. To this end, a considerable number of probes have been used heretofore, one example typified by that shown in U.S. Pat. No. 4,177,568. However, the standard probe in the industry for measuring coordinates remains the Renishaw probe.
Hence, there exists a need for a coordinate measuring means which overcomes the disadvantages present in previous coordinate measuring machines.